Data not loading correctly after transformations

Hello, I have some transformations and table joins I'm running in PBI. The very last transformation is a "group by" and it sums up a column.  When I view the data via "Transform data" and go to the very last step, the data is showing correctly.  Once I click "apply and close" and then create a matrix table with those columns, the totals don't match up.

In this screenshot, I'm looking at a sum for the last column called DT by a certain month and location.  For Houston item # 63, the total should be 209 and for item #65 the total should be 187.

Once I create a matrix, the numbers don't match up anymore. Now, item#63 is sum 187 and item #65 is sum 170.

There are no relationships to this table and no filters on my screen either.  

Does anyone have any advice if they've seen this before?